The present invention relates to the inspection of a workpiece and more specifically to a method for inspecting a workpiece for quality control purposes during a production run in which workpieces are supplied to workstations by an autoloader.
In many manufacturing processes, only finished parts are inspected at the completion of a production run. In some manufacturing processes, however, periodic inspections of workpieces are performed after the completion of certain operations during a production run. One particular type of manufacturing process that commonly utilizes such periodic inspections is a machining line, wherein a sequence of machining operations are performed on a workpiece by different types of workstations. Usually, a plurality of workstations for performing a particular machining operation are provided. An example of a machining line that often utilizes periodic inspections is the machining line for a crankshaft, wherein a raw crankshaft from a casting operation is subjected to a series of turning, grinding, tapping, drilling and polishing operations.
Conventionally, a machining line often includes one or more sub-lines, wherein a single workpiece conveyance apparatus is used to supply workpieces to workstations that perform different machining operations. In order to inspect a workpiece from a particular workstation in such a mixed operation sub-line, the workpiece conveyance apparatus has to be stopped and the workpiece has to be removed from the workstation by hand. In addition to presenting ergonomic concerns, this stoppage of the entire workpiece conveyance apparatus is inefficient.
More recently, a machining line has been developed, wherein the machining line includes a plurality of zones or segments dedicated to a particular machining operation. In each such segment, a workpiece conveyance apparatus moves workpieces to and from a plurality of workstations that perform the same operation. With this type of setup, in order to inspect a workpiece, the workpiece conveyance apparatus still has to be stopped and the workpiece still has to be removed from the workstation by hand. Accordingly, the aforementioned problems with the machining lines having mixed operation type of sub-lines are still present in the segment or zone type of machining lines.
Accordingly, there is a need in the art for a more efficient method of inspecting a workpiece for quality control purposes during a production run. The present invention is directed to such a method.